Molecular Phylogenetics of the Callitrichidae with an Emphasis on the Marmosets and Callimico

Abstract

We have recorded long calls of free ranging groups of six Callithrix species, looking for species-specific parameters in the physical structure of the vocalizations. This comparative study is the first time a behavioral character (vocalization) has been incorporated in a study on Callithrix taxonomy. The long calls were analyzed in a digital sonograph and statistical comparisons performed, using analysis of variance. The data show that each of the six analyzed taxa can be distinguished on the basis of its call structure, mainly using the first long call note or syllable. In agreement with analyses based on morphological and genetic data, the vocalizations support the division of Callithrix into two groups: a jacchus-group and an aurita-group. The first group encompasses C. jacchus, C. geoffroyi, C. penicillata, and C. kuhlii, and the second, C. aurita, and C. flaviceps. Vocal parameters are able to distinguish all the taxa within each group, even C. flaviceps and C. kuhlii, whose specific status has been questioned. Differences between the four taxa of the jacchus-group suggested by vocalization data are not identical to those inferred on the basis of some morphological data. It is possible that vocalization differences are also influenced by historical secondary contact between populations and could have evolved as mechanisms of specific recognition and reproductive isolation. The results indicate that vocalization is a behavioral character that can be used to supplement other taxonomic data to study the phylogeny of the Callitrichidae and to improve our understanding of the evolution of the reproductive isolation of natural populations.